The purpose of research and development for a positioning navigation technology aims to estimate a location of a moving carrier during a moving process in actual environment, so as to achieve an accurate and stable navigation requirement of the moving carrier. As such, automatic guided vehicles nowadays are generally installed with a positioning module such as Global Position System (GPS) for outdoor usage or Indoor Global Position System (iGPS) for indoor usage. Theoretically, the positioning module should provide sufficient information that is accurate and stable for the autonomous mobile vehicles to complete their tasks, however, an accuracy and a reliability of the positioning information may be substantially reduced due to restrictions of the positioning module in nature or influences from external environment.
In recent years, besides the positioning module utilizing a wireless radio-frequency signal, the automatic guided vehicles may also be additionally installed with additional devices such as auxiliary positioning devices including an encoder, an electronic compass and the like, so as to increase the accuracy and the reliability for positioning. It has always been a research focus for researchers as how to integrate positioning information of those additional devices with the information generated by the wireless positioning device in order to generate the required location information.
Currently, a common integration method includes a mode switching method and a weight allocation method and the like. However, although various application examples have been proposed according to aforesaid methods, those methods cannot instantly response to changes in the environment to sufficiently use the positioning effect provided by said auxiliary devices because not all of states of the unknown environment can be obtained in advance. For instance, the wireless positioning module may not be able to perform the positioning accurately and stably in some specific regions due to blocking of obstacles or signal interference. In other words, it is now one of most concerned issues for person skilled in the art as how to develop a positioning method and a path planning navigation method for responding to the changes in the environment.